The deep peroneal nerve is a small branch of the common peroneal nerve. The deep peroneal nerve innervates the web space between the first and second toes. The nerve crosses over the anterior tibial artery from medial to lateral just proximal to the ankle joint near the surface of the distal tibia. The deep peroneal nerve can appear as a homogeneous hypoechoic structure surrounded by hyperechoic fat without polyfascicular echotexture. The deep peroneal nerve is more difficult to image in the proximal leg.¹ This probably relates to the course of the nerve and its division into a large number of motor branches.²

Ultrasound guidance may provide some advantages over landmark-based approaches to deep peroneal nerve block. One study reported the use of ultrasound improved the onset of deep peroneal nerve block at the ankle although the overall quality of this block was no different.³ Another study has reported high success rates with deep peroneal nerve blocks that combine ultrasound with nerve stimulation.⁴